The Effect of the Timing of Umbilical Cord Clamping on Hemoglobin Levels, Neonatal Outcomes and Developmental Status in Infants at 4 Months Old.

Objectives
Delayed umbilical cord clamping (DCC) increases blood transfer to newborns. Hence we investigated the effect of the timing of DCC on hemoglobin levels, neonatal outcomes and developmental status in infants at four months old.


Materials & Methods
This clinical trial examined infants born to 400 pregnant women immediately upon birth and at the age of four months in Isfahan, central Iran in 2016. A table of random numbers was used to randomly allocate the newborns to intervention group with a 90-120-sec delay in umbilical cord clamping and the control group with a clamping delay of below 60 sec, and blood samples were taken from their umbilical cords. The Ages and Stages Questionnaire was used to evaluate the infants' developmental status.


Results
Umbilical cord hemoglobin was significantly higher in the intervention group compared to in the controls (P=0.024). No significant differences were observed between the two groups in terms of neonatal complications except neonatal jaundice was significantly more common in the intervention group (P=0.025), although the need for phototherapy was not different between the groups. Overall, no significant differences were observed between the two groups in terms of developmental status at four months old; however, the infants had better problem-solving skills in the DCC group (P=0.015).


Conclusion
Despite elevating hemoglobin, DCC has no effects on infant development except in terms of problem-solving skills. Further studies are recommended on the effects of DCC on infant development.


Materials & Methods
This clinical trial examined infants born to 400 pregnant women immediately upon birth and at the age of four months in Isfahan, central Iran in 2016. A table of random numbers was used to randomly allocate the newborns to intervention group with a 90-120-sec delay in umbilical cord clamping and the control group with a clamping delay of below 60 sec, and blood samples were taken from their umbilical cords. The Ages and Stages Questionnaire was used to evaluate the infants' developmental status.

Results
Umbilical cord hemoglobin was significantly higher in the intervention group compared to in the controls (P=0.024). No significant differences were observed between the two groups in terms of neonatal complications except neonatal jaundice was significantly more common in the intervention group (P=0.025), although the need for phototherapy was not different between the groups. Overall, no significant differences were observed between the two groups in terms of developmental status at four months old; however, the infants had better problem-solving skills in the DCC group (P=0.015).
words, human development depends on a dynamic and continuous interaction between biological and acquired factors (5). Iron deficiency anemia is associated with developmental disorders in children (13). Iron deficiency affects language, cognitive, socio-emotional and sensory development in children and associated with various neurocognitive impairments (14,15).
Children with chronic anemia during infancy received lower motor scores compared to children with proper iron levels (16). High hemoglobin level upon birth constitutes an iron reserve for dealing with iron deficiency anemia in infants, which accounts for 30%-50% of pregnancy complications in developing countries (10,17,18).

Materials & Methods
The

Results
The results obtained showed no significant differences between the two groups in terms of the mothers' mean age ( Table 1).
The mean and standard deviation of birth Apgar score in the intervention group was 9.82±0/26 and in the controls was 9.74±0/48. No significant differences were observed between two groups.
The mean level of umbilical cord blood hemoglobin was significantly higher in the intervention group compared to in the controls; the infants in the intervention group had developed jaundice more frequently than the controls, although there were no significant differences between the two groups in terms of the need for phototherapy ( Table 2).
Studying the infants in terms of the different dimensions of their development at four months old showed problem-solving to be the only dimension in which the two groups differed, as the intervention group received higher scores for it (P=0.015) nevertheless, no significant differences were observed in terms of the other dimensions and the overall score ( Table 3).

Discussion
We should that DCC could positively affect the hemoglobin level in infants. The relationship between infants' hemoglobin level 24-48 h was investigated after birth and the timing of umbilical cord clamping in them (27). Moreover, higher hemoglobin levels were revealed in the DCC group (29), which was consistent with the present findings. Higher hematocrit was reported at 4 h of birth in DCC group (30).
No significant differences were found between the two groups examined in terms of the effect of the timing of umbilical cord clamping on hemoglobin levels, although serum ferritin levels were 45% higher in the DCC group than in the early clamping group, suggesting a statistically significant difference; however, no cases of iron deficiency anemia in these groups were observed (31). Early umbilical cord clamping could reduce hemoglobin levels in infants at two months old and that a delay in clamping, even by two minutes, can increase iron reserves in term infants and thus improve their blood status before age six months (32). The timing of umbilical cord clamping had a significant effect on blood volume and red blood cell mass and that holding the infant below the level of the placenta and a few minutes of delay in clamping the umbilical cord can increase the infant's blood volume by 40% (33). Iron plays a role in many central nervous system functions in fetuses and infants. The main effect of iron is on the myelination process and the main ganglia functions and it also reduces neurometabolic activity (15,16). Iron deficiency negatively affects the function of iron-dependent enzymes in all cells and contributes significantly to the function of neurotransmitters and muscles (10,16). DCC was effective in improving hemoglobin levels and anemia status (34). DCC has been shown to improve iron stores in infants to 6 months of age (35).
The present study found no significant differences between the two groups in their dimensions of development, including communication, gross and fine motor skills and personal-social development; however, they differed in terms of problem-solving.
A clinical trial was conducted to examine the effect of delayed umbilical cord clamping on infants' development at four months old and found better problem-solving skills in the delayed umbilical cord clamping group, which is consistent with the present findings (36). The Ages and Stages Questionnaire scores had no differences between late and early clamping (27). Anemia affects the communication aspect of development and causes delays in it (9, 37), while Perez et al. found this relationship insignificant (38). A significant relationship was found between anemia and motor delays (16, 38). Hemoglobin levels did not affect the personal-social dimension of development (9), which is consistent with the present findings.
Infants in the intervention group had developed jaundice more frequently than the controls, although there were no significant differences between the two groups in terms of the need for phototherapy.
However, the amount of required phototherapy for jaundice in the early cord clamping group was less than the late cord clamping group (27).
No difference was reported in hyperbilirubinemia between two groups (29). The present study found higher mean Apgar scores in the intervention group compared to in the controls, although the difference was not statistically significant. There were no significant differences The Effect of the Timing of Umbilical Cord Clamping on Hemoglobin Levels between early and late clamping for the neonate's Apgar score less than seven at five minutes (27,29). Significant differences were observed between the early clamping group (30 sec after birth) and the delayed clamping group (3 min after birth) in terms of the 1-min and 5-min Apgar scores (33).
Besides, significantly higher 5-min Apgar scores were found in the group of preterm infants with DCC compared to in the early clamping group (39), but no significant the Apgar score was reported at 5 min between two groups (40).
In conclusion, delays in umbilical cord clamping can significantly elevate umbilical cord hemoglobin levels; however, it also increases the risk of neonatal jaundice and has no effects on developmental status, except in the problem-solving dimension.
Further studies are recommended on this subject.

Acknowledgement
We are thankful to all colleagues who helped us with this research. Special thanks go to the officials of Shahid Beheshti University of Medical Sciences and women who participated in the study.

Authors' contribution
Soheila Nouraie: Interpretation of data, data collection, analysis and interpretation of data